The present invention relates to conveyor systems, and more particularly, a conveyor system wherein the movement of load carrying units moved by a continuously moving conveyor are individually controlled.
Conveying systems are typically used in manufacturing facilities to move workpieces through various workstations located along the conveying path.
Conveyor systems known to me include conveyors which move at a constant speed and include load carrying units which can be coupled for movement therewith between workstations and uncoupled from the conveyor so that they will be stationary at the workstations while work is done on a workpiece carried by the load carrying units. These conveyor systems work well wherein all of the workpieces are the same or otherwise require the same amount of work time at each workstation along the conveyor path.
However, in many manufacturing operations, a mix of workpieces requiring different amounts of work time at the various workstations are moved on the same conveyor through the various workstations. This operating condition creates a problem with these conventional type conveyor systems because of the different work times required to perform work on workpieces carried on successive load carrying units. For example, if the succeeding load carrying units are carrying workpieces requiring a lesser amount of work time than the workpieces on a preceding load carrying unit stopped at a workstation, the succeeding load carrying units will be stacked up at the entrance to the workstation waiting for the work to be performed on the workpiece on the preceding load carrying unit in the workstation. This situation creates bottlenecks in the smooth, timely flow of workpieces through the various downstream workstations along the conveyor path.
Other conveyor systems known to me include conveyors which move at a constant speed and load carrying units which are coupled and uncoupled to the conveyor for moving workpieces through workstations located along the conveyor path as work is being performed on the workpieces without stopping the load carrying units carrying the workpiece. The load carrying units are stopped, however, at a final station whereat the finished workpiece is removed from a load carrying unit and an unfinished workpiece is placed on the load carrying unit to be moved through the workstations. These conveyor systems work well wherein all of the workpieces are of the same type or otherwise require the same amount or work at each workstation along the conveyor path. However, in many manufacturing operations, a mix of different workpieces requiring different amounts of work time through each workstation are continuously moved on the same conveyor through various workstations. This situation requires a uniform spacing between all of the load carrying units with the space being determined by the maximum work time or any one of the workpieces carried by all of the load carrying units and therefore requires the use of an inordinately long conveyor and is inefficient in the use of valuable floor space in a manufacturing facility.